The invention is directed to a process for the production of optically active 1-benzyl-3,4-bis(diphenylphosphino)-pyrrolidine of the formula ##STR1## in which Ph indicates a phenyl group.
This pyrrolidine derivative is described in old, not yet published German application P3403194.4 published Aug. 1, 1985 as German OS No. P3403194 (and the related Beck U.S. application Ser. No. 688,360 filed Jan. 2, 1985, the entire disclosure of which is hereby incorporated by reference and relied upon) as a chiral ligand in rhodium complexes, and there is also described the use of the rhodium complexes as catalysts for the homogeneous hydrogenation of unsubstituted or .beta.-substituted .alpha.-acylamino acrylic acids. The process for the production of the pyrrolidine derivative also described in the above-mentioned German application and Beck U.S. application requires an extraordinarily large number of steps and consequently is quite cumbersome and protracted.
There has now been found a new process for the production of the compound 1-benzyl-3,4-bis(diphenylphosphino)-pyrrolidine in only three proces steps in a relative simple manner.